This invention relates generally to fluid carrying pipe arrangements and is particularly directed to a casing spacer for maintaining proper spacing between an inner carrier pipe and an outer casing.
In pipelines it is frequently necessary to position one or more pipes carrying a liquid medium within a rigid outer casing. This carrier pipe within an outer casing arrangement is frequently provided for water and sewer mains within highway and railroad crossing pipe casings to maintain carrier pipe alignment, restrain the carrier pipe against flotation or other movement, or maintain the carrier pipe in a fixed position and orientation such as per grade requirements in the case of a gravity sewer.
One prior approach to positioning a carrier pipe within an outer casing involves banding wooden skids to the outer periphery of the carrier pipe with steel straps. This approach is undesirable in that it requires at least two workers to attach the wooden skids to the carrier pipe, is cumbersome and time consuming to install, and frequently results in the catching of the wooden skids on welded beads resulting in rotation of the carrier pipe and destabilizing of its joints. The wooden skids and steel straps are subject to breaking, making removal and reinstallation necessary. These banded wooden skids have generally been replaced by casing spacers comprised of stainless steel, galvanized steel, or epoxy coated steel. This type of casing spacer typically includes upper and lower semi-circular shell members coupled together along their adjacent edges by means of plural nut and bolt combinations inserted through flanges on adjacent edges of the casing spacer""s shell members. Disposed about the outer peripheries of the shell members in a spaced manner are plural risers which maintain the carrier pipe in a fixed orientation and in spaced position from the outer casing as well as from other pipes within the casing. This approach also suffers from limitations such as the limited gripping engagement of the carrier pipe by the casing spacer allowing the spacer to move along the length of the carrier pipe resulting in reduced support and position stability for the carrier pipe. In addition, the one-half sections of the casing spacer are sized to accommodate a carrier pipe having a specific circumference requiring another casing spacer with different sized shell members to accommodate a carrier pipe of a different size. Finally, this latter approach, while easier to install and more reliable than earlier banded wooden skids casing spacers, still requires two workers and a considerable amount of time for installation.
The present invention addresses the aforementioned limitations of the prior art by providing a casing spacer comprised of a high-strength, pliable material which is capable of securely maintaining an inner carrier pipe in fixed position within an outer casing. The present casing spacer is comprised of plural connected shell members disposed about and engaging the outer surface of the carrier pipe, where shell members of different sizes may be incorporated in the casing spacer to accommodate a wide range of carrier pipe circumferences.
Accordingly, it is an object of the present invention to facilitate the positioning of a carrier pipe within an outer casing.
It is another object of the present invention to provide a casing spacer comprised of plural connected shell members for positioning between an inner carrier pipe and an outer casing which is adapted for use with and attachment to carrier pipes having a wide range of outer circumferences by using, in combination, spacer shell members of different sizes.
A further object of the present invention is to provide a casing spacer comprised of a lightweight, high-strength, pliable material which is easily assembled and installed between an inner carrier pipe and an outer casing.
Yet another object of the present invention is to provide a casing spacer for use between an inner carrier pipe and outer casing which has a low coefficient of friction to facilitate its installation and includes one or more non-slip members for securely engaging the outer surface of the carrier pipe in a fixed manner when installed.
The present invention contemplates a casing spacer disposed between and engaging an inner carrier pipe carrying a fluid material and an outer casing having a generally circular cross section, the casing spacer comprising plural shell members each having an arcuate inner portion disposed about and engaging the carrier pipe and risers disposed on and extending outward from said arcuate inner portion for engaging the outer casing; a coupling for connecting the plural shell members and maintaining the plural shell members in fixed, spaced position about the carrier pipe, wherein the casing spacer maintains the carrier pipe in fixed position within and spaced from the outer casing; and a positioning member attached to an arcuate inner portion of at least one of the shell members for frictionally engaging the carrier pipe and maintaining the casing spacer in a fixed position on the carrier pipe.